This prospective experimental study compares two methods for replacing an endotracheal tube in Thiel-embalmed body donors. The conventional method uses an airway exchange catheter based on the Seldinger technique, whereas the investigational method uses a flexible bronchoscope to provide direct visual guidance throughout the exchange.

The primary outcome is the duration of interrupted ventilation, measured from cessation of ventilation until ventilation is resumed through a correctly positioned replacement tube. Secondary outcomes include unsuccessful tube exchange requiring complete reintubation, duration of individual procedural steps, procedures lasting more than 60 seconds, use of additional rescue equipment, and unforeseen technical difficulties.

Both techniques will be performed in two Thiel-embalmed donated human bodies using an alternating sequence. Four experienced physicians will perform 40 tube exchanges per technique, resulting in a total of 80 procedures.

Endotracheal tube exchange may be required because of cuff failure, inappropriate tube size, tube damage, luminal obstruction, or the need for a planned intervention. During conventional tube exchange over an airway exchange catheter, continuous visualization of the subglottic airway and trachea is not possible. Consequently, advancement of the replacement tube may fail or may result in airway injury.

The bronchoscopic tube-exchange technique is intended to provide continuous visual control throughout the procedure and immediate confirmation of the replacement tube position.

The study will be conducted using two human bodies donated for medical education and research and preserved using the Thiel embalming method. Before each experimental series, the donated body will be intubated with a 7.5-mm endotracheal tube, and tracheobronchial secretions will be suctioned.

Two experienced physicians in intensive care medicine and anesthesiology will perform the conventional airway exchange catheter-guided technique, and two experienced pulmonologists will perform the bronchoscopic technique. To minimize order, learning, and tissue-wear effects, the techniques will be alternated. The starting technique will differ between the two body donors.

Each physician will perform 10 tube exchanges per body donor using the assigned technique, resulting in 20 procedures per physician, 40 procedures per technique, and 80 procedures overall.

Procedure timing will be based on predefined start and end points. The primary interval begins when ventilation is interrupted and ends when ventilation is resumed through the correctly positioned replacement tube. A trained observer will record procedural times, individual procedural steps, technical difficulties, use of additional equipment, and unsuccessful exchanges using a standardized source document.

Where feasible, video or photographic documentation may be used to verify procedure timing and technical events. The face will remain covered to prevent identification of the body donor.

Continuous outcomes will be analyzed using the paired Wilcoxon signed-rank test. Paired dichotomous outcomes will be analyzed using the McNemar test. Descriptive statistics will include medians, interquartile ranges, and ranges.

Inclusion Criteria:

• Human body donor preserved using the Thiel embalming method.
• Intact trachea without relevant postmortem or preparation-related lesions.
• Documented consent for scientific use of the body and confirmation of anatomical suitability by the Institute of Anatomy.
• Sufficient mobility of the neck, jaw, and laryngeal region to permit realistic tube-exchange maneuvers.

Exclusion Criteria:

• Tumor or stenosis involving the larynx, trachea, or central airways.
• Previous surgery or radiotherapy involving the larynx or oral cavity.
• Previous pneumonectomy.
• Previous tracheotomy or laryngectomy.
• Inability to achieve safe or standardized positioning of the cadaver.
• Incomplete consent documentation or unclear provenance.
• Preservation using a fixation method other than the Thiel method.